. Elements of biology; a practical text-book correlating botany, zoology, and human physiology. Biology. MOLLUSKS 265 oxygen from the water above. The clam industries of the eastern coast aggregate over $1,000,000 a year. Scallop. â The scallop, another highly esteemed mollusk, forms an important fishery. The scallop rests on one valve on the bottom in shallow water and if disturbed swims away by clapping the valves rapidly together. The single adductor muscle is eaten, whereas in the clam the soft parts of the body are used as i''ulgur, a univalve rnollusk common in Long Island Sound,
. Elements of biology; a practical text-book correlating botany, zoology, and human physiology. Biology. MOLLUSKS 265 oxygen from the water above. The clam industries of the eastern coast aggregate over $1,000,000 a year. Scallop. â The scallop, another highly esteemed mollusk, forms an important fishery. The scallop rests on one valve on the bottom in shallow water and if disturbed swims away by clapping the valves rapidly together. The single adductor muscle is eaten, whereas in the clam the soft parts of the body are used as i''ulgur, a univalve rnollusk common in Long Island Sound, which does much harm by boring into the shells of edible moUusks. A Univalve Shell. â Any large uni- valve shell, as Fulgur, may be used in the laboratory.^ The shell, which is one piece, is called a univalve. Notice the spiral arrangement of the shell. How-many turns does it make? The lines of growth run parallel, as in the clam, to the edge of the shell. Hold the openmg toward you. The opening is known as the aperture. When the animal is alive, part of the body is protruded through this. Draw the shell twice natural size, showing all above parts. Living Snail. â (Use the pond snail Limnea or Physa.) Watch the move- ment of living snails in the aquarium. The large fleshy mass which protrudes from the shell is called the foot. Try to decide how locomotion takes place as the animal moves along the side of the acfuarium. Watch the animal as it feeds. What kind of food docs this snail eat? Notice the position of the mouth. Is there any distinct head? These ani- mals are called gastropodss (stomach- footed). Do you see any reason for this name? P'ind the two tentacles or horns. Touch them with a pencil. What happens? Look for the dark eye-spots at the base of tentacles. Make any experiments you can to see if the snail can distinguish between light and darkness. (Cover part of the dish and Ica^e it for some minutes undisturbed.) Do you find any other structures protruding fr
Size: 2075px × 1204px
Photo credit: © Paul Fearn / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., boo, bookpublishernewyorkamericanbookcompany, booksubjectbiology
